JP-2026076361-A - Stator cores, electric motors, and generators

Abstract

[Problem] To provide a stator core that improves yield and manufacturing difficulties while achieving a high maximum magnetic permeability. [Solution] The stator core has a helical shape with a constant distance from the central axis and comprises a core wire portion made of electromagnetic soft iron wire and an insulating film covering the outer surface of the core wire portion. The half-width of the peak corresponding to the iron (220) plane in X-ray diffraction analysis of the core wire portion is 0.31 degrees or less. [Selection Diagram] Figure 2

Inventors

• 堀田　孝治
• 齋藤 達哉
• 上野 友之

Assignees

• 住友電気工業株式会社

Dates

Publication Date

20260511

Application Date

20260219

Priority Date

20231124

Claims (13)

1. It has a spiral shape with a constant distance from the central axis, and consists of a core wire made of electromagnetic soft iron or silicon steel, The core wire portion comprises an insulating film covering the outer surface of the core wire portion, A stator core in which the full width at half maximum of the peak corresponding to the iron (220) plane in the X-ray diffraction analysis of the core wire portion is 0.31 degrees or less.
2. The stator core according to claim 1, wherein the full width at half maximum of the peak corresponding to the iron (220) plane in the X-ray diffraction analysis of the core wire portion is 0.30 degrees or less.
3. The stator core according to claim 1 or 2, wherein, in a cross-section including the central axis, the insulating films covering adjacent core wire portions in a direction parallel to the central axis are in contact with each other.
4. The stator core further comprises a resin portion covering the insulating film, In the cross-section including the central axis, the resin portion is The first part covering the insulating film, located on the opposite side of the central axis when viewed from the core wire portion, A second part covering the insulating film located between the core wire portion and the central axis, The stator core according to claim 1 or claim 2, comprising at least one selected from the group consisting of third parts located between the insulating films covering adjacent core wire portions in a direction parallel to the central axis.
5. The stator core according to claim 4, wherein the resin portion is a cured body that adheres the insulating film covering the adjacent core wire portions in a direction parallel to the central axis.
6. The stator core according to any one of claims 1 to 5, wherein the cross-section perpendicular to the longitudinal direction of the core wire portion is rectangular.
7. The stator core according to any one of claims 1 to 6, wherein the height of the cross-section perpendicular to the longitudinal direction of the core wire portion, in the direction parallel to the central axis, is 0.6 mm or less.
8. The stator core according to any one of claims 1 to 7, wherein the insulating film is composed of an inorganic material.
9. The stator core according to claim 8, wherein the inorganic material is a phosphate salt.
10. The stator core according to any one of claims 1 to 9, wherein the thickness of the insulating film is 0.1 μm or more and 30 μm or less.
11. The stator core according to any one of claims 1 to 10, wherein the aspect ratio, which is the ratio of the length of the stator core in the direction parallel to the central axis to the outer diameter of the stator core, is 3 or more.
12. An electric motor comprising a stator core according to any one of claims 1 to 11.
13. A generator comprising a stator core according to any one of claims 1 to 11.

Description

This disclosure relates to stator cores, electric motors, and generators. This application claims priority under Japanese Application No. 2023-199294, filed November 24, 2023, and incorporates all the provisions of the said Japanese application. Stator cores, typically used in electric motors or generators, are manufactured by punching out electrical steel sheets. However, this method results in a significant amount of waste in the electrical steel sheet material, leading to low manufacturing yield. Furthermore, because these stator cores are constructed by stacking punched electrical steel sheets, manufacturing tall stator cores presents a challenge. To address these problems, a stator core in which thin sheet strips are wound in a helical shape has been proposed (see, for example, Patent Document 1). International Publication No. 2010/105866 The stator core according to this disclosure has a helical shape with a constant distance from the central axis and comprises a core wire portion composed of electromagnetic soft iron or silicon steel wire, and an insulating film covering the outer surface of the core wire portion. The full width at half maximum of the peak corresponding to the iron (220) plane in X-ray diffraction analysis of the core wire portion is 0.31 degrees or less. Figure 1 is a schematic perspective view showing the structure of the stator core in this embodiment.Figure 2 is a cross-sectional view corresponding to the section containing the central axis A in Figure 1 (a cross-sectional view along the line segment II-II in Figure 1).Figure 3 is a schematic cross-sectional view showing the structure of the core wire portion and insulating film that constitute the stator core.Figure 4 is a schematic flowchart of the manufacturing method for a stator core.Figure 5A is an enlarged cross-sectional view of a portion of the stator core in the first modified example.Figure 5B is an enlarged cross-sectional view of a portion of the stator core in a further modification of the first modification.Figure 5C is an enlarged cross-sectional view of a portion of the stator core in the second modified example.Figure 5D is an enlarged cross-sectional view of a portion of the stator core in the third modified example.Figure 5E is an enlarged cross-sectional view of a portion of the stator core in a further modification of the third modification.Figure 5F is an enlarged cross-sectional view of a portion of the stator core in the fourth modified example.Figure 5G is an enlarged cross-sectional view of a portion of the stator core in the fifth modified example.Figure 6 is a perspective view of the electric motor and generator in this embodiment.Figure 7 is a cross-sectional view taken along line XX in Figure 6.Figure 8 shows the relationship between the half-width of the peak corresponding to the iron (220) surface and the maximum permeability. [Issues this disclosure aims to address] A helical stator core, such as the one disclosed in Patent Document 1, improves yield and manufacturing difficulties. However, according to the inventors' research, such a stator core has the problem that the maximum magnetic permeability, which is an important characteristic of the stator core, is not sufficient. Therefore, one of the objectives of this disclosure is to provide a stator core that improves yield and manufacturing difficulties while achieving a high maximum magnetic permeability. [Effects of this disclosure] The above stator core improves yield reduction and manufacturing difficulties, while also providing a stator core capable of achieving high maximum magnetic permeability. [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described. The stator core of this disclosure is (1) It has a helical shape with a constant distance from the central axis and comprises a core wire made of electromagnetic soft iron or silicon steel, and an insulating film covering the outer surface of the core wire. The full width at half maximum of the peak corresponding to the iron (220) plane in the X-ray diffraction analysis of the core wire is 0.31 degrees or less. The inventors investigated the reasons why the maximum magnetic permeability is not sufficiently improved in a helical stator core having an insulating film. As a result, they obtained the following findings and arrived at the configuration of the stator core of this disclosure. When forming a wire made of soft iron or silicon steel into a helical shape, generally, a raw wire made of soft iron or silicon steel is prepared first, and a wire having a desired cross-sectional area and cross-sectional shape is obtained by performing a forming process on this raw wire. At this time, because the amount of processing in the forming process is large, a large strain is introduced into the wire. From the viewpoint of removing this strain, an annealing treatment is performed on the wire to reduce the strain, and then the wire is proce